Photographic apparatus for contact printing



J1me 1954 L. E. VAN DER GRINTEN 2,681,605

PHOTOGRAPHIC APPARATUS FOR CONTACT-PRINTING Filed March 28, 1951 4 Sheets-Sheet l PO 7- O u l 5 F g.1.

\-I I I 5 r 'INVENTOR LODEWIJ K EVERT VAN DER aRmn-m BY Q 0* AT ane s .June 22, 1954 L. E. VAN DER GRINTEN 2,681,605 PHOTOGRAPHIC APPARATUS FOR CONTACT-PRINTING Filed March 28, 1951 4 Sheets-Sheet 2 L6 w 5 Fig.3.

7 x 3 5 K Le Fig.4.

'INVEN'TOR A ORNEYS' June 1954 E. VAN DER GRINTEN 2,681,605

PHOTOGRAPHIC APPARATUS FOR CONTACT-PRINTING Filed March 28, 1951 4 Sheets-sheaf a QINVENTOR LODEWIJK EVERT vnupetekmmd Y P i AT Ram's June 1954 E. VAN DER GRINTEN 0 PHOTOGRAPHIC APPARATUS FOR CONTACT-PRINTING Filed March 28, 1951 4 Sheets-Sheet 4 F 8, mvENT R LODEWIJK EVERT VAN DER GRINTEN AT RNEYS Patented June 2 2, 1954 UNITED STATES PATENT OFFICE PHOTOGRAPHIC APPARATUS FOR CONTACT PRINTING erlands Application March 28, 1951, Serial No. 217,952

Claims priority, application Netherlands April 15, 1950 13 Claims.

The invention relates to photographic contactprinting apparatus comprising a panel of lighttransmitting material curved in one direction, i. e. linearly curved, having on its convex side a flexible applying apron for applying and pressing the material to be exposed onto the panel under tension, the said apron extending tangentially off the panel in the resting (i. e. feeding or loading) position of the apparatus and following the surface of the panel in the working position of the apparatus. Exposure apparatus of this type is known.

A simple form of such apparatus is found in the socalled printing windows or panels described in German patent specification No. 659,053. In that case the applying apron should be transpar cut. The operation of such apparatus is, however, not simple and the apparatus does not func tion faultlessly.

More complete contact printing apparatus with exposure from the concave side of the panel is described for example, in U. S. patent specification No. 2,024,678 and in British patent application No. 19,175/47. In this latter case the panel is rotatable about a central axis and the apron is wound and unwound on the panel by this rotation.

All these known forms of apparatus have the disadvantage that the original to be copied, after having been applied on the apron together with the copying material in the resting (i. e. feeding) position of the apparatus, has then to be set moving together with the apron. This may involve diificulties especially when the original or the copying material forms part of a larger aggregate (for example, when it is a page from a book), so that this larger aggregate, properly supported, also has to undergo the whole of this movement. During the movement the original gradually disappears from sight. Thus, if the copy material shifts or crumples during the movement, this cannot be seen and such shifting or crumpling cannot be controlled. It is an object of this invention to provide apparatus in which movement of the copy material is eliminated or reduced to a minimum.

The disadvantage referred to above can be avoided by arranging that the panel itself carries out a to and fro rolling movement between a resting position in which the panel and apron are apart and the apron lies tangentially to the panel and a working position in which the apron follows the contour of the panel. However, it is necessary then to achieve a high standard of accuracy in the curvature of the panel. Thus if at any point the panel is curved otherwise than in the direction of rolling movement the panel will tend to wobble during its travel and moreover there is a tendency for the apron lying between the panel and the supporting surface to wear non-uniformly. Furthermore any sharp particle of dust caught between the panel and the supporting surface may damage the surface of the panel or the apron.

It has now been found that these difilculties may be overcome by so constructing the apparatus that the panel in its rolling movement makes contact only at its curved margins with the supporting surface and according to the present invention a photographic contact-printing apparatus is provided which comprises a linearly curved exposure panel of light-transmitting material adapted be illuminated from the concave side thereof, an apron adapted to be laid close to the convex side of said panel following the contour of the panel and to sandwich between itself and the panel a sheet of light-sensitive material and an original sheet to be copied, means for rolling the panel to and fro between a resting position in which the panel and the apron are apart and the apron lies tangentially to the panel and a working position in which the apron follows the contour of the panel, and one or more members for supporting the panel during such rolling movement, the construction being such that during such rolling movement only the curved margins of the panel, or flanges secured thereto, bear against the supporting member or members.

Preferably the construction is in one of two forms: either the curved margins of the panel are provided with projecting flanges which run on a fixed supporting surface and thus hold the body of the panel proper from bearing contact with that surface, or the panel is caused to run on rails or tracks which bear only against the curved margins of the panel. In either case the apron lies Within the space between the bearing surfaces so that it is not itself brought into bearing contact with any other surface than that of the panel itself.

"Preferably also, according to the invention, one end of the apron is attached to the panel, or to the casing holding the panel, along a generating line of the panel and the other end forms a terminal edge which is thin and flat and is parallel to the generating lines of the panel. Preferably the said terminal edge is anchored in a fixed position within the apparatus.

The invention will now be described with reference to the accompanying drawings which illustrate preferred forms of the apparatus of the invention:

Figs. 1 and 2 illustrate one form of the invention in the resting and working positions respectively, in side elevation.

Fig. 3 is a front elevation from the right of Fig. 1.

Fig. 4 is a front elevation similar to Fig. 3, but in respect of a modified form of the apparatus.

Figs. 5 and 6 illustrate a further form of the invention, in the resting and working positions respectively, a supporting plate being used in this case; these drawings also illustrate how pages of a book can readily be copied by means of this apparatus.

Figs. 7 and 8 similarly illustrate another form of apparatus according to the invention.

Referring to Figs. 1, 2 and 3 the apparatus comprises a cylindrical panel I, in the centre of which a tube lamp 2 (usually a high-pressure mercury vapour lamp) is provided, the lamp 2 being supported by a frame 3 fastened at the two ends of the panel I.

The panel I is provided with marginal flanges 4, which rest on fixed rails 5 forming part of the frame of the apparatus. These rails 5 are con nected by means of transverse walls 5 (Fig. 3) and by bolts '1, so that a rigid system is formed. It will be clear from the drawings that the flanges 4 can roll on the rails 5 from the posi tion according to Fig. l to that shown in Fig. 2.

One end of the apron 9 is fastened to the edge 8 of the panel 1 and the other end is fastened by means of a rod it, running through a hem of the apron 9, and mounted in the projections ll. Thus, when the panel 5 rolls from the posttion shown in Fig. 1 to that shown in Fig. 2, the apron 9 is wound onto the panel, as indicated by the line extending over the convex side of the pane1 in Fig. 2. At the same time the original E2 which is to be copied, and the copying ma-- terial l3 underneath it, may be pressed between the panel and the apron 9 and thus be stretched across the panel l. When current is fed to the lamp 2 via the lead I49 and the said lamp begins to glow, the required copying operation takes place.

The apron 9 remains stretched because on either side of it (see Fig. 3) two belts 20 are provided, which have been wound onto the panel 1 in the opposite direction and leave the said panel tangentially at the place where the apron 9 runs onto the panel tangentially. The belts 29 are stretched by tension springs 2| fastened to fixed bearings 22. The other ends of the belts 2e are fixed at 23 on the panel. system (for this construction see also the co-pending application No. 19,1'75/47).

The apparatus shown in Fig. 4 differs from that shown in Figs. 1, 2 and 3 only in that in this case the panel is not provided with flanges on which to roll but instead the ends of the panel l roll directly on rails 5. The entire central part of the panel I, however, is free from any contact with a support surface, and if the panel should be liable to wear or scratching, this can only occur at the edges of the panel, i. e. the part of the panel which is not used for the print ing operation. In this form of apparatus the rails 5 are preferably covered with a coating of rubber or the like, at 15.

Figs. 5 and 6 illustrate an apparatus in which the free end of the apron 9a is connected at M to a plate Hi, which can rest freely on the supports I"! and by an abutment H" is held against lateral displacement to the left in Fig. 5. The curved panel la is provided on either side of the apron 9a with circular flanges 4a, which rest on the rails 5a also provided on either side of the apron 9a. Fig. 5 illustrates the resting position of the apparatus. The extreme edge 14 of the apron 9a, which is connected to the plate 46, is flat and thin, so that, when the apparatus is op-- erated from the right, a page 25 of a book 26 can be placed on the apron 9c, while the rest of the book 26 can remain below and beyond said edge i l. The book 26 rests on a fixed but adjustable support 2?. Since the end of the plate it has a 5 slight downward slope, the extreme edge Id can be inserted accurately far into the fold or spine of the book, across the slightly bulging pages of the book. When the book is placed in the apparatus on the support 2'1, the plate is with the apron M can easily be lifted, so that the edge M can be inserted into the fold of the book. The plate 56 need not then rest on the two supports i1.

When the cylinder la is rolled to the right on 3 the rails 5a with the aid of the flanges ie, the

apparatus will reach the position of Fig. 6 i. e. the working position. The slopes E8 of the rails 5a then cause the curved panel is to be lowered until, on reaching the working position, it touches the extreme edge M with its free edge, and thus the page from the book can be copied far into the fold. When the glass cylinder has passed beyond the left-hand part of the book, it is lowered as it were into the fold. In fact, the extreme edge i l of the apron 9a and plate It lies below the general level of apron 8a and plate 56. This general level (in the left-hand part of apron 9a and plate it) can be designated as being the geometrical locus of the line where the panel la and the apron 9 meet, i. e. approximately the plane defined by the successive lowest generating lines of the cylinder is.

The apparatus functions smoothly, and there is little, if any, wear of the panel. is the apron 91a, whereas such wear would occur, if the panel were to touch the plate Hi via the apron during the rolling movement. This apparatus is also provided with tensioning belts 2G fastened to the springs 2! as in the previous figures.

Figs. 7 and 8 illustrate an apparatus, again in the resting and working positions respectively, which is distinguished from the apparatus according to Figs. 5 and 6 in that the rails 579 have no sloping parts (l8) the same effect being, however, achieved by providing eccentric flanges 4?) on the panel. Their eccentricity is so chosen that the radius of the flanges, measured from the axis of the panel to the point touching the support in the working position, gradually decreases. The effect of this is that, on the one hand the panel and the apron do not touch the plate 16b during the rolling movement, while on the other hand, in the working position illustrated in Fig. 8, the free edge of the panel is brought to lie on the extreme edge Mb of the apron 91'; connected to the plate [6b. Thus, the panel descends onto the extreme edge I l-b again. In this apparatus it is also possible to copy pages of books. It is obvious that stops have to be provided for limiting the movement of the panel, i. e. so that the panel can move only between the desired resting and working positions.

The lamps 2 should be provided with screens for preventing the light from radiating outside the apparatus. These screens may act at the same time as reflectors. They can be movable in such a manner that that their position shifts in sympathy with the movement of the panel and so that the light is always cast correctly onto the panel.

What I claim is:

1. In a contact photoprinting apparatus, a rollable exposure member comprising a light pervious panel substantially in the form of a sector of a hollow cylinder, a support over which said panel is rollable bodily along a path-substantially tangent to the convex surface of the panel between a backward loading position and a forward exposing position, a flexible apron for applying sheet material to said panel for exposure, said apron being attached to said member extending forward from the backward edge of said panel over the convex panel surface and thence tangentially to a terminal edge at the forward end of the apron, said terminal edge being anchored at a forward part of said support and registering with the forward edge of the panel in said exposing position, tensioning means for holding said apron in stretched condition comprising spaced elongated flexible members attached to 2 said member and extending from the forward edge of said panel over said surface at either side of the apron and thence tangentially backward to end portions anchored at a backward part of said support, said member and said support respectively having ccengaging convex and relatively straight elongated bearing surfaces at either side of said apron, said relatively straight bearing surfaces extending along said path and said convex bearing surfaces being supported on and rollable along said relatively straight surfaces and supporting said exposure member so as to relieve the apron from the weight of said member during the rolling movements of said member.

2. In a contact photoprinting apparatus, an exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a backward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said tangential path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealon in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the weight of said member.

3. In a contact photoprinting apparatus, an exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a backward part of said support and an exthe forward rolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the Weight of said member, said convex bearing elements being flanges projecting from and curved in the direction of curvature of said panel surface.

4. In a contact photoprinting apparatus, an exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a forward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said tangential path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on saidv member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movcments so as to relieve the apron from the weight of said member, said support comprising spaced rails forming said relatively straight bearing elements.

5. In a contact photoprinting apparatus, an exposure member comprising a light-pervious panel having an other surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a forward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward path of said support, the apron extending forward front said surface substantially in said tangential path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the weight of said member, said support comprising spaced rails forming said relatively straight bearing elements and said convex bearing elements being marginal portions of said panel surface at either side of the area thereof overlaid by said apron.

6. In a contact photoprinting apparatus, an

exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily so as to roll said surface to and fro in a substantially straight path substantially tangent to said surface between a loading position at a backward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having an end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, elongated flanges projecting from said member and forming convex bearing elements at either side of the area of said surface overlaid by said apron, and relatively straight elongated spaced rails on said support forming a trackway along said path supporting said flanges for rolling movements therealong, said rails and flanges supporting said member in its rolling movements so as to relieve the apron from the weight of said member during such movements.

'7. In a contact photoprinting apparatus, an

exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a forward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said tangential path when said member is in loading position and being wrapped over said surface by the forwardrolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the weight of said member, said support comprising spaced rails forming said relatively straight bearing elements, said relatively straight bearing elements being generally horizontal but being inclined downward at a lo cation engaged by said convex elements as said member approaches said exposing position so that said member is biased by gravity to its exposing position.

8. In a contact photoprinting apparatus, anexposure member comprising a light-pervious 8 panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a forward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said tangential path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the weight of said member, said support comprising spaced rails forming said relatively straight bearing elements, said convex bearing elements being flanges projecting from and curved in the direction of curvature of said panel surface, said relatively straight bearing elements being generally horizontal, the height of projection of said flanges decreasing progressively toward the portions thereof engaged by said relatively straight elements in the exposing position of said member so that said member is biased by gravity to its exposing position.

9. In a contact photoprinting apparatus, an exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a leading position at a backward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, means continuously holding the apron under tension between said end portions so that the apron extends forward from said surface substantially in a fiat plane when said member is in loading position and so that said member wraps the apron tightly over said surface as it is rolled forward to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member said support at either side of said apron, convex bearing elements being supported on said relatively straight elements and being rollable therealong in the direction of said path, said elements supporting said member during its to fro rolling movements so as to relieve the apron from the weight of said member.

10. In a contact photoprinting apparatus, an exposure member comprisit-ig a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a backward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said tangential] path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the weight of said member, said other end portion of the apron comprising a transverse terminal edge, and means on said support holding said transverse terminal edge in an unobstructed position for insertion into the fold of a book.

11. In a contact photoprinting apparatus, an exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a backward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said tangential path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, and cengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the weight of said member, said other end portion of the apron compris ing a transverse terminal edge, and a flat plate held on said support beneath the apron and having a thin free edge positioning and stiffening said transverse terminal edge.

12. In a contact photoprinting apparatus, an exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a backward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said tangential path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the weight of said member, said other end portion of the apron comprising a transverse terminal edge, and a flat plate held on said support beneath the apron and having a thin free edge positioning and stiffening said transverse terminal edge, said plate being rockable relative to said support so that its free edge is movable downward for insertion into the fold of a book as said member is rolled to exposing position.

13. In a contact photoprinting apparatus, an exposure member comprising a light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support over which said member is rollable bodily to and fro along a path substantially tangent to said surface between a loading position at a backward part of said support and an exposing position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having one end portion held at said surface and another end portion held at a forward part of said support, the apron extending forward from said surface substantially in said tangential path when said member is in loading position and being wrapped over said surface by the forward rolling of said member to exposing position, and coengaging convex and relatively straight elongated bearing elements respectively on said member and said support at either side of said apron, said convex bearing elements being supported on said relatively straight bearing elements and being rollable therealong in the direction of said path, said elements supporting said member during its to and fro rolling movements so as to relieve the apron from the weight of said member, said other end portion of the apron comprising a transverse terminal edge, and a flat plate held on said support beneath the apron and having a thin free edge positioning and stiffening said transverse terminal edge, said plate being rockable relative to said support so that its free edge is movable downward for insertion into the fold of a book as said member is rolled to exposing position, portions of said bearing elements coacting to lower said member and cause it to rock said plate as it is rolled to exposing position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,093,509 Weidner Apr. 14, 1914 2,168,481 Jollasse Aug. 8, 1939 2,223,341 Ernst et a1 Dec. 3, 1940 2,292,668 Sheridan Aug. 11, 1942 2,535,145 Langdon Dec. 26, 1950 

